438 / 2022-08-15 13:59:27

Vision-based High Precision Frequency Detection with the Assistance of Non-Harmonic Analysis Technology

Frequency detection; Digital image correlation; Non-harmonic Fourier transform

Vision-based vibration measurement techniques are receiving increasing attention in the field of structural health monitoring, due to the fact that such methods can achieve non-contact measurements and have the advantages of simple systems and cost reduction. To address the shortcomings of low sampling rate and low accuracy faced by vision-based vibration measurement techniques, this paper proposes a method for frequency estimation using NHFA based on the acquisition of sub-pixel-level vibration data using digital image correlation. Through simulation and experimental verification, the proposed method can achieve frequency estimation with arbitrary accuracy without the limitation of sampling time, and even can achieve accurate frequency estimation without satisfying the Nyquist sampling theorem.